September 2, 2008

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Sept. 2, 2008) - Mantra Mining Inc. (TSX VENTURE:MAN) ("Mantra" or the "Company") is pleased to announce that it has entered into two separate agreements dated August 27, 2008 with affiliates of Rio Tinto PLC ("Rio Tinto") and NovaGold Resources Inc. ("NovaGold") and an affiliate of NovaGold, to purchase a 100% interest in mineral claims comprising over 485,000 acres in Alaska, including the undeveloped world class Arctic polymetallic deposit and several early stage base and precious metal exploration properties (collectively, the "Acquisition"). Upon completion of the Acquisition, Mantra will be one of the significant mineral property holders in Alaska.

Overview of Acquisition

Mantra has agreed to purchase the interests of Rio Tinto and NovaGold in the Ambler Project which consists an area of about 87,972 acres consisting of 1,138 State of Alaska claims as well as 17 patented (privately owned) mining claims comprising about 35,000 acres, covering a major portion of the precious-metal-rich Ambler volcanogenic massive sulfide ("VMS") belt.

In addition, Mantra has agreed to purchase 100% of NovaGold's interest in five other properties located in Alaska comprising about 397,560 acres that are either held directly or under option by an affiliate of NovaGold, as follows:

More detailed information concerning the properties being acquired by Mantra can be found below under the headings "Ambler Project" and "Geological and Other Information on the Properties" and on the Company's website: www.mantramining.com.

The consideration payable by Mantra for the mineral properties consists of $29 million payable to Rio Tinto in cash and common shares of Mantra over a 24 month period from the initial closing and $20 million payable to NovaGold in common shares of Mantra over a 15 month period from the initial closing. See "Terms of Acquisition".

The initial closing of the Acquisition will occur following receipt of all necessary regulatory approvals, including the approval of the TSX Venture Exchange, and Mantra being in a position to complete, concurrently with the initial closing, a private placement for gross proceeds of a minimum of $C3 million.

Rick Van Nieuwenhuyse is a director of Mantra and a director and officer of NovaGold.

Ambler Project

The Ambler Project includes the Arctic deposit located in the southern Brooks Range of NW Alaska approximately 290 kilometers (180 miles) southeast of Red Dog mine, the world's largest zinc mine, and approximately 45 kilometers (30 miles) north of the small village of Kobuk. The Arctic deposit is one of several VMS deposits known in the Ambler Schist sequence of the southern Brooks Range.

NovaGold has reported that, based on the NI43-101 Technical Report dated February 12, 2008 prepared by SRK Consulting (US), Inc. ("SRK") for NovaGold, the Ambler Project has resources of 16.8 Million tonnes (Mt) of Indicated and 11.9 Mt of Inferred as outlined in the table below:

For supporting information and additional information, refer to the SRK Technical Report which is available on www.sedar.com under NovaGold's profile. SRK is currently updating the Report for Mantra. The Report will be filed by Mantra prior to the initial closing of the Acquisition.

Mr. Chowdhry, the President of Mantra stated, "The Ambler Project ranks as one of the largest and richest undeveloped VMS deposits in the world based on the SRK resource estimate on the Arctic deposit. The purchase of a 100% interest in the Ambler Project will allow the Company's experienced management team to advance this extraordinary asset towards production and establish the Company as one of the newest players in the copper sector capable of delivering excellent value to our shareholders."

NovaGold's exploration team has completed nearly 3,000 meters of core drilling in five holes at Ambler in the most recent 2007 exploration program. Two of the exploration holes identified the existence of a deeper fold structure containing the same stratigraphy as the Arctic massive sulfide deposit. These drill results outline an area of approximately 4.5 square kilometers of productive stratigraphy within drill depth below and adjacent to the Arctic deposit, indicating that significant exploration potential remains for further expansion. The Arctic deposit is undeveloped and has not been proven to be economic. Further studies will be undertaken to demonstrate its viability.

Terms of Acquisition

Rio Tinto is the owner of the claims comprising the Ambler Project, subject to an option agreement (the "Ambler Option Agreement") with NovaGold under which NovaGold has the right to acquire a 51% interest in the Ambler Project by completing approximately US$7 million in remaining earn-in expenditures on the Project by 2016. Rio Tinto has a back-in right to acquire 2% of NovaGold's interest at the joint venture stage.

Mantra has agreed to acquire Rio Tinto's interest in the Ambler Project in consideration for $29 million, payable as follows:

(a) 3,125,000 common shares of Mantra, having a resale restriction for a period of 12 months following the initial closing date, at a deemed price of $1.60 per share having an aggregate value of C$5 million to be issued to Rio Tinto on the initial closing of the Acquisition;

(b) US$12 million is payable in cash on or before the date that is 15 months from the date of the initial closing of the Acquisition (the "First Cash Payment"); and

(c) US$12 million is payable in cash on or before the date that is 24 months from the date of the initial closing of the Acquisition (the "Second Cash Payment").

In the event that Mantra fails to make the First Cash Payment to Rio Tinto, Rio Tinto may elect to either terminate Mantra's right to acquire the Ambler Project under its agreement with Rio Tinto and under the Ambler Option Agreement or require Mantra to pay interest on the outstanding principal amount of the First Cash Payment at the Royal Bank of Canada Prime Rate plus 4% until the First Cash Payment is paid in full. In the event that Mantra fails to make the Second Cash Payment, Mantra will retain its rights under the Ambler Option Agreement, but Rio Tinto may elect to either terminate Mantra's right to acquire the Ambler Project under its agreement with Rio Tinto or require Mantra to pay interest on the outstanding principal amount of the Second Cash Payment at the Royal Bank of Canada Prime Rate plus 4% until the Second Cash Payment is paid in full.

Mantra has also agreed to grant Rio Tinto a 1% net smelter returns royalty in respect of minerals produced from the Ambler Project, subject to Mantra's right to purchase such royalty at any time for US$10 million.

In addition, Mantra has agreed to acquire NovaGold's interest in the Ambler Option Agreement in consideration for US$15 million, payable as follows:

(a) 3,125,000 common shares of Mantra having a resale restriction for a period of 12 months following the initial closing date, at a deemed price of $1.60 per share having an aggregate value of C$5 million to be issued to NovaGold on the initial closing of the Acquisition; and

(b) 6,250,000 common shares of Mantra at a deemed price of $1.60 per share having an aggregate value of C$10 million to be issued to NovaGold on or before the date that is 15 months from the date of the initial closing of the Acquisition in accordance with a subscription receipt to be issued to NovaGold by Mantra on the initial closing.

Mantra has also agreed to reimburse NovaGold for all direct expenditures incurred by it or its affiliate on account of the Ambler Project from June 1, 2008 up to the date of the initial closing of the Acquisition. The reimbursement is limited to a maximum of $2 million and must be made within 30 days of the initial closing.

In addition, Mantra has agreed to concurrently acquire NovaGold's interest in the five other Alaskan properties referred to above for C$5 million payable on the initial closing of the Acquisition by issuing to NovaGold an aggregate of 3,125,000 common shares of Mantra, having a resale restriction for a period of 12 months following the initial closing date, at a deemed price of $1.60 per share.

Mantra will acquire 100% of NovaGold's interest in the Ambler Option Agreement and the five other Alaskan properties on the date of the initial closing.

Conditions to Initial Closing

Completion of the initial closing of the Acquisition is subject to a number of conditions including, but not limited to, the completion of satisfactory due diligence, Manta being in a position to complete, concurrently with the initial closing, a private placement for gross proceeds of a minimum of $C3 million, the approval of the TSX Venture Exchange and other necessary regulatory and stock exchange approvals. The agreement with Rio Tinto is subject to completion of the acquisition by Mantra of NovaGold's interest in the Ambler Option Agreement. There can be no assurance that the Acquisition will be completed as proposed or at all.

Mantra will not be required to obtain shareholder approval under TSX Venture Exchange policies.

Capitalization of Mantra on Initial Closing

Mantra currently has 45,839,801 common shares issued and outstanding. In addition, there are 1,325,000 stock options outstanding under its stock option plan and 281,312 common share purchase warrants outstanding.

Upon completion of the initial closing of the Acquisition, Mantra expects its non-diluted capitalization to be approximately as follows (assuming no stock options or common share purchase warrants are exercised prior to the initial closing of the Acquisition and excluding common shares issued in a private placement expected to be completed prior to the initial closing):

-------------------------------------------------------------------- ------ ____________________________________________________Number of Capitalization________________________________________ Shares__ Percentage -------------------------------------------------------------------- ------ Currently issued and outstanding common shares____ 45,839,801________83.02% -------------------------------------------------------------------- ------ Common shares issuable to Rio Tinto on initial______3,125,000________ 5.66% closing of the Acquisition -------------------------------------------------------------------- ------ Common shares issuable to NovaGold on initial______ 6,250,000________11.32% closing of the Acquisition(1) -------------------------------------------------------------------- ------ Total(1)__________________________________________ 55,214,801______ 100.00% -------------------------------------------------------------------- ------ (1) These figures do not include the issuance to NovaGold of an additional ____6,250,000 common shares on or before the date that is 15 months from ____the date of initial closing of the Acquisition.

NovaGold will become an insider of Mantra on the initial closing of the Acquisition. Assuming the capitalization described in the table above, NovaGold will hold approximately 11.32% of the issued and outstanding common shares of Mantra on the initial closing of the Acquisition. In addition, Mantra has agreed to issue to NovaGold an additional 6,250,000 common shares on or before the date that is 15 months from the date of initial closing of the Acquisition in respect of the acquisition of NovaGold's interest in the Ambler Option Agreement.

Management Changes

Mantra does not expect any changes to its board of directors or management team on the initial closing of the Acquisition. Raj Chowdhry said: "Mantra's Board of Directors has significant experience working in Alaska. Our ability to partner with local communities and Alaskan Native Corporations will greatly assist in advancing the Ambler Project to a production decision."

Under the agreement with NovaGold, Mantra will grant NovaGold the right to nominate one director for election at each shareholders meeting following the completion of the Acquisition so long as NovaGold and its Affiliates collectively beneficially own 10% or more of the issued shares of Mantra as of the date that Mantra gives notice of a meeting of its shareholders at which directors will be elected.

Proposed Work Program

In the SRK Technical Report, additional activities in support of a pre-feasibility assessment having aggregate indicative costs of US$3,100,000 were recommended, consisting of:

Mantra intends to complete further in-fill drilling to improve resource definition (upgrade Inferred resources to Measured and Indicated resources) as well carry out further exploration drilling to expand the known resource. In addition, Mantra intends to undertake engineering and metallurgical studies and environmental baseline work in order to scope out a development plan and Preliminary Economic Assessment report.

Geological and Other Information on the Properties

Ambler Project

The Ambler district occurs within an east-west trending zone of Devonian to Jurassic submarine rocks. VMS deposits and prospects are hosted in the Middle Devonian to Early Mississippian Ambler Schist Belt, a sequence of metamorphosed bimodal volcanic and volcanoclastic rocks interbedded with tuffaceous, graphitic and calcareous metasedimentary rocks. VMS mineralization can be found along the entire 110 km (68 miles) strike length of the district.

The Arctic deposit is one of several polymetallic VMS deposits known in the Ambler Schist Belt. The deposits include the Sun, Smucker, Sunshine, Picnic Creek and Dead Creek deposits.

Within the Arctic deposit area, five main lithologic suites are recognized and include:

Mineralization at Arctic is dominated by chalcopyrite, pyrite, sphalerite and lesser galena often with minor barite which occur as stratiform semi-massive to massive sulfide horizons up to 20+ meters in thickness. Footwall alteration is characterized by Mg-chlorite and locally talc, while hanging-wall alteration is characterized by sericite and paragonite.

The mineralization at Arctic occurs as a series massive to semi- massive sulfide lenses on the limb of an overturned isoclinal fold lying roughly 200 meters or less below surface and dipping moderately to the west. Detailed stratigraphic and structural interpretation shows that the lower limb is overturned and that potential exists to expand the deposit along the lower upright limb of the fold structure.

Baird Project - NW Alaska

The Baird Mtns project consist of 502 state of Alaska mining claims covering 80,560 acres in the Baird Mountains 35 miles north of Kiana, Alaska, in the south part of the western Brooks Range. NovaGold owns 442 of the state claims and has the option to acquire a 60% to 100% interest in the remaining 60 state claims constituting the Omar property owned by Teck-Cominco. The property covers rolling to mountainous terrain in the southern Brooks Range along the Squirrel River. Exploration is helicopter-supported either from Kiana a small native village along the Kobuk River which drains into Kotzebue Sound or from seasonal camps established on the property.

The project area contains a folded and faulted sequence of Paleozoic age limestone and dolomite (Baird Group) which host strong concentrations of copper and zinc. Mineralization in the Baird Mountains shares a Cu-Zn-Pb-Ba-Co-Ge-F geochemical signature with the large Ruby Creek deposit and other showings at Bornite 100 miles to the east. Important mineral occurrences which cover a roughly 20 by 12 kilometer area are the Omar prospect (on the optioned Teck Cominco property); and the Frost, Deadfall, Powdermilk and Peak prospects on NovaGold ground.

Colorado Creek Property - Central Alaska

The Colorado Creek project area is located approximately 70 km northwest of McGrath, and 410 km northwest of Anchorage in low rolling hills roughly midway between the Kuskokwim and Yukon Rivers. The Colorado Creek claim group consists of 274 Alaska state claims owned by Rosander Mining Company and leased by NovaGold covering 27,040 acres. The project is located in and around the historical and ongoing placer mining operations at Colorado Creek. Some camp facilities exist on the property and an airstrip serviceable by Hercules aircraft support exploration on the property.

Rocks in the Colorado Creek project area include the Upper Cretaceous Cripple Creek Mountains (CCM) volcanic-plutonic complex, and a series of slightly younger felsic rhyodacite dikes, all of which intruded the Cretaceous Kuskokwim Group, a thick sequence of shale, greywacke, and minor conglomerate.

The Colorado Creek property shows similar geologic and geochemical relationships to the +30 million ounce Donlin Creek gold deposit located 100 kilometers (65 miles) to the south where mineralization are associated with the felsic porphyry rhyodacite dikes and sills. These rhyodacite intrusives are distinctive magnetic lows in comparison with the volcano-plutonic complexes which are distinctive magnetic highs. Much of the mineralization in the Colorado Creek area is related to dikes and sills in and around the NE-trending Ermine fault zone along the northwest side of the Cripple Creek Mountains.

The Kugruk prospect lies 70 miles north of Nome in the northern Seward Peninsula and consists of 1113 Alaska state claims and 4 leased claims covering over 177,000 acres. The property covers low tundra-covered hills and broad valleys along the Kugruk River which runs south to north through the claim block. Only very limited rock exposure is present. Exploration is helicopter supported from the historic Independence mining camp located roughly in the center of the property and approximately 20 miles from the coast and Kotzebue Sound.

The Kugruk area consists of Late Proterozoic and Paleozoic schists, quartzites, and carbonate cut by a major NNW trending structure called the Kugruk Fault. On the west of the fault, late Cretaceous granitoid rocks intrude the metasedimentary sequence and include the Kugruk Pluton dated at 94.9 Ma. The area is best known for placer gold occurrences which occur in many of the tributaries of both the Kugruk River and the Kiwalik River to the east.

Omalik Property - Eastern Seward Peninsula, Alaska

The Omalik prospect lies 90 miles northeast of Nome on the west flank of the Darby Mountains, and 30 miles north-northeast of Golovin Bay. The property consists of 123 Alaska state mining claims totaling 19,680 acres.

The Omalik prospect lies moderately close to the Kugruk property and contains high grade Ag-Pb-Zn mineralization within marbles of the Nome group Paleozoic sediments. Several occurrences of this mineralization are found scattered in a 5.5 by 4.5 mile area trend. Other parties control two of the high grade showings.

Tintina Properties - Southwest Alaska

The Tintina prospects consist of several claim blocks staked on reconnaissance geochemistry and geophysics in the Kuskokwim region of southwest Alaska south of the small community of Aniak. Four individual claims blocks are part of the project and include the Ash, Timber, Kipchuk and Cone claims totaling 583 Alaska state mining claims covering 93,280 acres. The claims roughly lie 20 to 40 miles south of Aniak in low rolling hills flanking the Aniak River. Exploration is helicopter supported and staged from Aniak where a jet accessible airstrip and local accommodations are available.

The properties cover a series of upper Cretaceous felsic rhyodacite dikes intruding the Kuskokwim Group sediments and are analogous with the Donlin Creek deposit further north in the same geologic setting.

Qualified Person

Robert McLeod, is a Qualified Person for the purposes of National Instrument 43-101 and has reviewed and approved the information of a scientific or technical nature contained in this news release.

ON BEHALF OF THE BOARD OF DIRECTORS

Raj Chowdhry, C.A., President & CEO

Cautionary Notice: This release may contain forward-looking statements regarding the Company's business or financial condition. Actual results could differ materially from those described in this news release as a result of factors, including, but not limited to the following: additional drilling, sampling and resource valuations, engineering and construction timetables, financial arrangements, developments in world resource markets, political developments in Alaska, the timing of regulatory and environmental approval and other factors. With respect to additional exploration, actual events may differ from current expectations of the Company or its joint-venture partners and other factors. The Company cautions that these and similar statements involve risk and uncertainties and are qualified by important factors, including competitive pressures, unfavorable changes in regulatory structures, and general risks associated with business, which could cause actual results to differ materially from those in the forward looking statement. Forward- looking statements are made in the context of information available as of the date stated. The Company undertakes no obligations to update or revise such statements to reflect new circumstances or unanticipated events as they occur, unless required by applicable law.